And you would have to find some one to build you custom parts. Which isn't cheap.

Zach Kerber (who specializes in Kohler v-twins) was asked about them once. He said he wouldn't even mess with one because of the weight. Not practical to build parts for a engine that only a few would want to try to run.

I can't remember for sure, but if you want custom rods made he will do it for $300-$400 per rod. His off the shelf rods are MUCH cheaper.

You can build a kohler v-twin for less money that will smoke any flathead.